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deploymentansiblehaproxy

Ansible release with serial: 50% for two different backend in haproxy

I have the following configuration in haproxy.

backend 1

machine-1 machine-1.com:8080 
machine-2 machine-2.com:8080 
machine-3 machine-3.com:8080 
machine-4 machine-4.com:8080
machine-5 machine-5.com:8080 
machine-6 machine-6.com:8080 
machine-7 machine-7.com:8080 
machine-8 machine-8.com:8080 
machine-9 machine-9.com:8080 
machine-10 machine-10.com:8080 

backend 2
machine-11 machine-11.com:8080 
machine-12 machine-12.com:8080

Serial is set to 50% in ansible rolling deployment.We also change the state of the machines to maintenance in this window. Thus ansible puts machine 1-6 in maintenance mode in the first go while making 7-12 as maintenance in the second go.

As it puts 7-12 as maintenance in the second go; the backend 2 cluster has no nodes online to take the traffic. This causes a huge number of issues on the application side.

How should I remediate this? I am using ansible 2.0.0.

EDIT 1

Two solutions that I can think of

  1. Make two releases for two backends
  2. replace one machine from 1-6 with one machine in backend 2, say 11.

Looking for solutions other than these. more in the line of using ansible to solve it.

Solution

  • Creating a host groups for each backend and run the update for each backend group in a separate run would be IMHO the best solution. If there is no way to do that it is possible to define batch sizes as a list since Ansible 2.2.

    So this should work:

    - name: test play
  hosts: backend servers.
  serial:
  - 5
  - 1